This is a friend's recipe for Kahlua - it will make several bottles. The alcohol content works out to about 16% (32 proof). A note - this does need to steep for about a month, so if you're planning on making it, start early.
Dissolve the coffe crystals in one cup of the water.
Bring the remaining water to a boil and dissolve the sugar in it.
Add the coffee to the sugar solution and heat almost to a boil.
Add the alcohol and decant into dark containers (this makes 7-8 cups; a fifth (750 mL) is just over 3 cups, so about 2 1/2 750 mL bottles- or just double it, make 5 bottles, and give some gift bottles).
Break the bean into several pieces and divide between the bottles.
Seal the bottles tightly and let them stand for 30 days before serving.